The manufacture of semiconductor devices involves the performance of a series of processing steps using a variety of high-tech production and metrology tools in a certain order and often within a certain period of time (such as Q-time). The primary function of a wafer logistics system in a wafer fabrication facility, or “fab,” is to deliver the wafers to each of the tools at the right time, as well as to track the location and status of the wafers throughout the process.
Automated material handling systems, AMHS, are applied to wafer fabs to carry out automated functions more efficiently, consistently, and safely than can be done via manual means. While growth in wafer size from 200 mm to 300 mm or 450 mm has rendered the fabrication process more economical in some respects, it has also placed additional demands on the process. Such demands include the necessity for cross-floor and cross-phase transportation and increased transportation volume, the combination of which often results in traffic jams.
Although existing devices and methods to deliver wafers have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects. Consequently, it would be desirable to provide a solution for improving the delivery of wafers.